scholarly journals Ultrastructural changes in the vessels and capillaries of the choroid and in the retina of rats caused by a mixture of alcohols (40% ethanol and 100% methanol)

2019 ◽  
Vol 79 (3) ◽  
pp. 58-63
Author(s):  
N. Molchaniuk
Keyword(s):  
Toxic Effect ◽  
Ganglion Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Photoreceptor Cells ◽  
Ultrastructural Changes ◽  
Retinal Area ◽  
Pathological Changes ◽  
Rpe Cells ◽  
Pure Methanol

We was study the ultrastructure of blood vessels and capillaries of the choroid (CO), retina's pigment epithelium (RPE), it's photoreceptor cells, ganglion cells, shoots of Muller cells of rats, that surround them, after in traperit one alinjection of a mixture of alcohols (40% ethanol and 100% methanol) in a 3:1 ratio and separately pure methanol (the methanol dose in each group was 0.75 g/kg rat body weight) in a PEM-100-01 electron microscope (Ukraine) in the period from 1 h10 min to 14 days after the alcohols injection. It was shown that the most sensitive structures to the toxic effect of a mixture of alcohol swere endothelial cells of CO and RPE cells. Pathological changes in RPE cells consistin alteration of mitochondria, in destructi on of the elements of the smooth endoplasmic reticulum and other organelles, in alignment of folds on the basal side of the cell sand in the destruction of apical microvilli. Significant destructive changes in its cells were not as early as 1 h10 min after ijection. In the dynamics of the study 1 h 10 min to 14 days the phenomenon of hydropic dystrophy and elements of destruction of organelles in the studied cells gradually progressed with simultaneous enhancement in the cells of the compensatory-restorative processes. After the injection of pure methanol, pathological changes in the chronic retinal area and in the retina are unidirectional except for the first 3 hours. Ethanol potentiates the toxic effect of methanol in the initial observation terms and leads to deeper damage to the rat CO and RPE ultrastructure. The leading place in the amplification of pathological changes in the investigated structures, after injection of the alcohols' mixture, is given to methanol.

scholarly journals Dynamics of ultrastructural changes in the chorioretinal complex of rat eyes induced by high dose of methanol

2016 ◽  
Vol 71 (1) ◽  
pp. 36-40
Author(s):  
N. Molchanyuk
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Ultrastructural Changes ◽  
High Dose ◽  
Regenerative Processes ◽  
Retinal Photoreceptor ◽  
Local Destruction ◽  
Destructive Processes

The structure of chorioretinal complex (CRC) of rat eyes was studied by electron microscopy: choriocapillaris, retinal pigment epithelium (RPE) and retinal photoreceptor cells after 40 minutes, 1 hour and 10 minutes, on the first 1 st , 3 rd , 7 th and 14 th days after a single intraperitoneal injection of methanol in a dose of 7.0 g/kg of body weight. It was shown that the primary and significant destructive changes in the structures of the studied complex were observed in the RPE cells, which are characterized by alteration of mitochondria and tubules of smooth endoplasmic reticulum, equation of basal folds and local destruction of the apical microvilli. The destructive processes in the cells were growing in the dynamics of CRC structures research. In parallel, the features of compensatory-regenerative processes in these cells were detected.

Ultrastructural Changes of Smoooth Endoplasmic Reticulum in the Retinal Pigment Epithelium by Choline Chloride

1972 ◽  
Vol 30 ◽  
pp. 58-59
Author(s):  
Kazushige Hirosawa ◽  
Eichi Yamada
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cell ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Choline Chloride ◽  
Retinal Pigment ◽  
Ultrastructural Changes ◽  
Lower Vertebrate ◽  
Visual Cells ◽  
Pigment Epithelial

The pigment epithelium is located between the choriocapillary and the visual cells. The pigment epithelial cell is characterized by a large amount of the smooth endoplasmic reticulum (SER) in its cytoplasm. In addition, the pigment epithelial cell of some lower vertebrate has myeloid body as a specialized form of the SER. Generally, SER is supposed to work in the lipid metabolism. However, the functions of abundant SER and myeloid body in the pigment epithelial cell are still in question. This paper reports an attempt, to depict the functions of these organelles in the frog retina by administering one of phospholipid precursors.

JAM-C maintains VEGR2 expression to promote retinal pigment epithelium cell survival under oxidative stress

2017 ◽  
Vol 117 (04) ◽  
pp. 750-757
Author(s):  
Xin Jia ◽  
Chen Zhao ◽  
Qishan Chen ◽  
Yuxiang Du ◽  
Lijuan Huang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Retinal Pigment Epithelium ◽  
Cell Survival ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelium Cell ◽  
Photoreceptor Cells ◽  
Rpe Cells

SummaryJunctional adhesion molecule-C (JAM-C) has been shown to play critical roles during development and in immune responses. However, its role in adult eyes under oxidative stress remains poorly understood. Here, we report that JAM-C is abundantly expressed in adult mouse retinae and choroids in vivo and in cultured retinal pigment epithelium (RPE) and photoreceptor cells in vitro. Importantly, both JAM-C expression and its membrane localisation are downregulated by H2O2-induced oxidative stress. Under H2O2-induced oxidative stress, JAM-C is critically required for the survival of human RPE cells. Indeed, loss of JAM-C by siRNA knockdown decreased RPE cell survival. Mechanistically, we show that JAM-C is required to maintain VEGFR2 expression in RPE cells, and VEGFR2 plays an important role in keeping the RPE cells viable since overexpression of VEGFR2 partially restored impaired RPE survival caused by JAM-C knockdown and increased RPE survival. We further show that JAM-C regulates VEGFR2 expression and, in turn, modulates p38 phosphorylation. Together, our data demonstrate that JAM-C plays an important role in maintaining VEGR2 expression to promote RPE cell survival under oxidative stress. Given the vital importance of RPE in the eye, approaches that can modulate JAM-C expression may have therapeutic values in treating diseases with impaired RPE survival.

A Morphometric Analysis of Early Effects of Ethanol on Hepatocyte Organelles from Peromyscusmaniculatus

1998 ◽  
Vol 4 (S2) ◽  
pp. 1064-1065
Author(s):  
J. T. Ellzey ◽  
J. P. Drake ◽  
L. Dader ◽  
P. Boentges
Keyword(s):  
Endoplasmic Reticulum ◽  
South Carolina ◽  
Morphometric Analysis ◽  
Smooth Endoplasmic Reticulum ◽  
Ultrastructural Changes ◽  
Deer Mice ◽  
Pathological Changes ◽  
Genetic Stock ◽  
Early Effects ◽  
Hanta Viruses

Pathological changes of hepatocytes from rats fed a 30% ethanol-derived calories diet for three weeks include noticeable ultrastructural changes including steatosis and hypertrophy of the smooth endoplasmic reticulum. We sought to examine hepatocytes of deer mice administered ethanol in an inhalation chamber for two weeks to determine if subtle changes occur in hepatocyte organelles prior to steatosis.Two strains of Peromyscus maniculatus, ADH-positive possessing hepatic cytosolic alcohol dehydrogenase and ADH-negative deer mice lacking this enzyme were purchased from the Peromyscus Genetic Stock Center (Univ. of South Carolina). They tested negatively for Hanta viruses. A morphometric analysis of the ultrastructure of ADH+(n=14) and ADH- (n=14) controls as well as experimentals exposed to chronic, intoxicating levels of ethanol was conducted. Blood ethanol levels were maintained between 1.25-1.75 mg/ml for two weeks in the experimentals.

scholarly journals Vertebrate features revealed in the rudimentary eye of the Pacific hagfish (Eptatretus stoutii)

2020 ◽  
Author(s):  
Emily M. Dong ◽  
W. Ted Allison
Keyword(s):  
Ganglion Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
List Type ◽  
Eye Evolution ◽  
The Pacific ◽  
Pigmented Epithelium ◽  
Cell Layers ◽  
Eptatretus Stoutii

SUMMARYHagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens, and a retinal architecture built of three cell layers – the photoreceptors, interneurons & ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable Pax6+ ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the rh1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homolog of gnathosome Retinal Pigment Epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina that differentially express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.HIGHLIGHTSHagfish eyes are degenerate but not degenerating, i.e. rudimentary but growingRetinal interneurons discovered implying ancestral hagfish had derived retinas & visionDespite lacking pigment, a Retinal Pigmented Epithelium homolog functions in hagfishRevised synapomorphies illuminate the dimly lit origins of vertebrate eye evolutionGRAPHICAL ABSTRACT

scholarly journals CRISPR-engineered mosaicism rapidly reveals that loss of Kcnj13 function in mice mimics human disease phenotypes

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Hua Zhong ◽  
Yiyun Chen ◽  
Yumei Li ◽  
Rui Chen ◽  
Graeme Mardon
Keyword(s):  
Gene Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Mutant Mice ◽  
Wild Type ◽  
Cell Degeneration ◽  
Rpe Cells ◽  
Mosaic Expression

Abstract The era of genomics has demanded the development of more efficient and timesaving approaches to validate gene function in disease. Here, we utilized the CRISPR-Cas9 system to generate Kcnj13 mutant mice by zygote injection to verify the pathogenic role of human KCNJ13, mutations of which are thought to cause Leber congenital amaurosis (LCA), an early-onset form of blindness. We found that complete loss of Kcnj13 is likely postnatal lethal. Among surviving F0-generation mice examined, 80% show mosaic KCNJ13 expression in the retinal pigment epithelium (RPE). Mosaic expression correlates with decreased response to light and photoreceptor degeneration, indicating that Kcnj13 mutant mice mimic human KCNJ13-related LCA disease. Importantly, mosaic animals enable us to directly compare Kcnj13 mutant and wild-type RPE cells in the same eye. We found that RPE cells lacking KCNJ13 protein still survive but overlying photoreceptors exhibit cell degeneration. At the same time, wild-type RPE cells can rescue neighboring photoreceptor cells that overlie mutant RPE cells. These results suggest that KCNJ13 expression is required for RPE cells to maintain photoreceptor survival. Moreover, we show that CRISPR-Cas9 engineered mosaicism can be used to rapidly test candidate gene function in vivo.

Membrane turnover in rod photoreceptors: ensheathment and phagocytosis of outer segment distal tips by pseudopodia of the retinal pigment epithelium

1987 ◽  
Vol 230 (1260) ◽  
pp. 339-354 ◽  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Excitatory Amino Acid ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ultrastructural Changes ◽  
Membrane Turnover ◽  
Rhodamine Phalloidin ◽  
Cytoplasmic Matrix ◽  
Rpe Cells

We have documented the ultrastructural changes that occur within the photoreceptor outer segment and the retinal pigment epithelium (rpe) during photosensitive membrane turnover. We employed an in vitro eyecup preparation from Xenopus laevis in which a large shedding event was induced by adding the excitatory amino acid l-aspartate (Green-berger & Besharse I985; J . comp . Neurol . 239. 361-372). We found that during L-aspartate-induced shedding the rpe cells formed. on their apical domains, previously undescribed processes that were directly involved in disc phagocytosis. These processes are structurally similar to processes formed by macrophages during phagocytosis and are accordingly referred to as pseudopodia. Pseudopodia were distinguishable from the apical villous process normally extended from the rpe in that they were closely applied to the surface of the outer segment, had a cytoplasmic matrix of low electron density that was devoid of most cellular organelles and were enriched in thin (7 nm diameter) filaments. Filament size, specific pseudopodial staining with the actin-specific probe rhodamine phalloidin and inhibition of pseudopod formation by cytochalasin D suggested that the thin filaments were composed of actin. Pseudopodial formation also occurs during a normal light-initiated shedding event. However, the low frequency of shedding, the asynchrony of the individual shedding events and the transient appearance of the pseudopodia prevented a full appreciation of their role during normal disc shedding. Associated with massive shedding and pseudopodial formation, there was an increased adherence between retina and rpe. During l-aspartate treatment, the apical portions of the rpe cells partitioned with the distal outer segment during retinal isolation. This effect was directly related to the development of pseudopodia and may reflect alteration of surface features of the rod outer segment (ros)-rpe interface related to phagocytosis. Our observations show that transiently forming pseudo­podia are the organelles of phagocytosis and that they may play a role in disc detachment as well.

scholarly journals The Impact of the Timing of Dosing on the Severity of UNC569-Induced Ultrastructural Changes in the Mouse Retina

2020 ◽  
Vol 48 (5) ◽  
pp. 669-676
Author(s):  
Ayako Sayama ◽  
Keiko Okado ◽  
Mayu Yamaguchi ◽  
Naozumi Samata ◽  
Masako Imaoka ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Electron Microscopic Examination ◽  
Photoreceptor Cells ◽  
Ultrastructural Changes ◽  
Mouse Retina ◽  
Visual Cycle ◽  
Electron Microscopic ◽  
The Impact

Mer proto-oncogene tyrosine kinase (MerTK), expressed in the retinal pigment epithelium (RPE), regulates the phagocytosis of shed photoreceptor outer segments. To investigate the influence of dosing time on MerTK inhibitor UNC569-induced retinal toxicity, UNC569 at 100 mg/kg was orally administered to male mice at 2 different Zeitgeber times (ZT5.5 or ZT22) for 28 days. Electron microscopy was conducted at ZT2 after the final dosing. Additionally, the visual cycle components (11-cis-retinal, all-trans-retinal, all-trans-retinol, and 11-cis-retinol), which play an important role in maintaining retinal homeostasis, were quantified by liquid chromatography/mass spectrometry/mass spectrometry. Under electron microscopic examination, the number of phagosomes and phagolysosomes in the RPE increased in both the ZT5.5 and ZT22 administered groups, while endoplasmic reticulum dilatation in the RPE and chromatin aggregation of photoreceptor nuclei were observed only in the ZT22 administered group. No change was observed in any of the visual cycle components. These results suggest that the timing of the dosing in relation to the physiological MerTK phosphorylation affected the severity of changes in the RPE, leading to the apoptosis of the photoreceptor cells.

scholarly journals Effect of methanol on the ultrastructure of chorioretinal complex of rats’ eyes in the early stages of the experiment

2014 ◽  
Vol 18 (1 (69)) ◽  
Author(s):  
N. І. Molchanyuk
Keyword(s):  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Electron Microscopic ◽  
White Rats ◽  
Intraperitoneal Dose ◽  
A Cell ◽  
Number Of Cells ◽  
Observation Period

Electron-microscopic structure of the chorioretinal complex were investigated (СRC), [choriocapillaries (HC) – retinal pigment epithelium (RPE) – photoreceptor cells (FC)], of white rats in a period of 40 min. to 3 days after a single intraperitoneal dose of methanol 0.75 g/kg body weight. It has been established that RPE cells are the most responsiveto the dose of the methanol used. In the dynamics (from 40 min. up to 3 days), they grew destructive changes of mitochondria and elements of smooth endoplasmic reticulum, the smoothness of the basal folds and patchy destruction of the apical microvilli. The changes in CC and FC were similar. By the end of the observation period, these phenomena in the CRC structure spread to a larger number of cells. At the same time, during the whole period of the study, and, in particular, after a day, some signs of recovery of compensatory nature were obvious. Attention is drawn to pronounced reaction of mitochondria, which are energy forming structures of a cell.

scholarly journals Vertebrate features revealed in the rudimentary eye of the Pacific hagfish ( Eptatretus stoutii )

2021 ◽  
Vol 288 (1942) ◽  
pp. 20202187
Author(s):  
Emily M. Dong ◽  
W. Ted Allison
Keyword(s):  
Ganglion Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Photoreceptor Outer Segments ◽  
The Pacific ◽  
Cell Layers ◽  
Eptatretus Stoutii ◽  
Animal Vision ◽  
Ciliary Marginal Zone

Hagfish eyes are markedly basic compared to the eyes of other vertebrates, lacking a pigmented epithelium, a lens and a retinal architecture built of three cell layers: the photoreceptors, interneurons and ganglion cells. Concomitant with hagfish belonging to the earliest-branching vertebrate group (the jawless Agnathans), this lack of derived characters has prompted competing interpretations that hagfish eyes represent either a transitional form in the early evolution of vertebrate vision, or a regression from a previously elaborate organ. Here, we show the hagfish retina is not extensively degenerating during its ontogeny, but instead grows throughout life via a recognizable PAX6 + ciliary marginal zone. The retina has a distinct layer of photoreceptor cells that appear to homogeneously express a single opsin of the RH1 rod opsin class. The epithelium that encompasses these photoreceptors is striking because it lacks the melanin pigment that is universally associated with animal vision; notwithstanding, we suggest this epithelium is a homologue of gnathosome retinal pigment epithelium (RPE) based on its robust expression of RPE65 and its engulfment of photoreceptor outer segments. We infer that the hagfish retina is not entirely rudimentary in its wiring, despite lacking a morphologically distinct layer of interneurons: multiple populations of cells exist in the hagfish inner retina and subsets of these express markers of vertebrate retinal interneurons. Overall, these data clarify Agnathan retinal homologies, reveal characters that now appear to be ubiquitous across the eyes of vertebrates, and refine interpretations of early vertebrate visual system evolution.

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